As many as 4% of adults have engaged with images of child sexual abuse on the internet and 16% of young women receive unwanted sexual requests online each year, academic research reveals.

The extent of web-facilitated exploitation is detailed in a series of reports for the next strand of hearings at the independent inquiry into child sexual abuse (IICSA), looking into the role of the internet, which starts on Monday.

Three separate studies assessing the latest research have been released as the week-long session begins at the IICSA’s headquarters in London.

One, a report by a team at Huddersfield University, estimates that as many as a tenth of adults in England and Wales take part in “online sexualised conversations” with children and teenagers aged under 18.

Last year the NSPCC reported that police forces in England and Wales recorded 5,653 incidents in 2016-17 of sexual crimes against children and young people in the UK in which there was an online element to the crime – up 44% from the previous year.

Between a quarter and a third of perpetrators who send unwanted sexual requests or who engage in grooming are female, according to international studies.

“It is unlikely that the proportion of adults in England and Wales who engage with images of child sexual abuse would fall below [the] more conservative estimate of 4%,” the report states.

It adds: “It would be fair to assume that no less than 5% of young men and 16% of young women receive unwanted sexual requests each year. Young women are between two and three times more likely than young men to receive unwanted online sexual requests and to be targeted by online groomers.”

About 1% of online images of child sexual abuse available globally are produced by people living in the UK, a study in 2013 found, while 6.5% of the demand for such images comes from people living in the UK.

The Huddersfield University report concluded: “The online world is safe for most young people.” That was partially due to the efforts of organisations such as police agency the Child Exploitation and Online Protection Command, the Internet Watch Foundation, the NSPCC and Barnardo’s to “enhance the safety of the online spaces” and partially to increased familiarity with online risks among parents and young people.

It cautioned, however, that almost a quarter of child sex abuse images were produced through covert means without the victim’s awareness and a growing proportion were computer-manipulated images of photographs.

The second report to IICSA, by researchers at Lancaster University, warns that 11- to 14-year-olds are most at risk from online abuse. Different studies have found that between 15% and 48% of children take part in sexting.

“Girls feel under more pressure to send self-generated sexual content and appear to be more harmed by it if the image is shared again,” the study notes.

A third report, by the independent institute NatCen Social Research, profiled perpetrators. It found that those convicted of online child sexual abuse were “generally male, white, young, educated, intelligent, employed, and have less prior criminal history than contact offenders”.

Typically, it adds, they “experience problems with intimacy, emotional loneliness, low self-esteem, under-assertiveness and empathy” that lead to difficulties in developing and maintaining relationships with others.

“Online offenders,” it observes, “may also suffer from depression and/or various personality disorders, as well as other mental health issues. However, this is not unique to this offending group and shares parallels with the more substantial contact offending research base.”